Colloid Cyst of the Third Ventricle

Clinical History

A 36-year-old man presented to the imaging department to examine intermittent headaches for a period of about three years, which respond poorly to symptomatic treatments, using CT tomography. He denied head trauma or special medical history.

Imaging Findings

A 36-year-old men was admitted with a 3 year history of intermittent headaches. There were no abnormalities upon clinical examination. Non-contrast CT of the head showed a rounded lesion at the roof of the 3rd ventricle, unilocular, although limited, regular contours, spontaneously hyperdense without hydrocephalus. With a maximum diameter of 12 x 10 mm [Fig 1, 2, 3]. Our patient was treated surgically by transcortical transventricular resection of the cyst without complications.

Discussion

Colloid cysts of the third ventricle are a benign epithelial lined cyst. Although usually asymptomatic, they can rarely present with acute and profound hydrocephalus and can cause sudden death [1]. The headaches are initiated, exacerbated, or relieved by a change in position and are characterized as brief, lasting seconds to minutes.
Colloid cysts account for 15-20% of intraventricular masses. They are located at the foramen of Monro in 99% of cases. The majority of cases are identified in early middle age (30-40 years of age) although 8% of cases may be diagnosed in paediatric age [2]. Familial cases of colloid cyst are extremely rare [3].
Classically these cysts are identified as well-delineated hyperattenuated masses on nonenhanced CT [1], attached to the anterosuperior portion of the third ventricle, unilocular, without calcification, isodense and hypodense cysts are uncommon. On MRI they are usually hyperintense on T1 and isointense on T2 weighted images. Some have central low T2 and high peripheral T2 signal, others have a homogeneously high signal. Peripheral rim enhancement may be present in some cases. CT tomography and magnetic resonance imaging (MRI), were described as improvement for morphologic evaluation.
There are usually no differential diagnoses for a colloid cyst. In atypical cases we can evoke other diagnosis namely: giant cell astrocytoma, calcified or hyperdense meningioma, pilocytic astrocytoma and blood in the region of foramen of Monro.
A colloid cyst, although a benign tumour, is surgically challenging because of its deep midline location. Early detection and total excision of the colloid cyst carries an excellent prognosis [1].

Differential Diagnosis List

Final Diagnosis

Colloid Cyst of the Third Ventricle

URL:	https://www.eurorad.org/case/13404
DOI:	10.1594/EURORAD/CASE.13404
ISSN:	1563-4086